There are separate settings for the home page, new tab page, address bar search, and search bar/search box. You should be able to add a new engine to the search bar/search box without affecting anything else, but if you installed an extension, it has the power to change the others.

Your "More system details" didn't include a list of your extensions, so please try this. Go to to the following tab and disable ALL nonessential, unrecognized, or newly added extensions, then restart Firefox:

orange Firefox button (or Tools menu) > Add-ons > Extensions category

Then restart Firefox and try updating your home page here:

orange Firefox button (or Tools menu) > Options > General

If you restart Firefox again, does the change stick?

Let us know if there are any other areas of damage that need repair.

All I had to do was select tools, hit options and change home page to google and bing went away, because it was no longer my home page. Thank you for trying to help me.

Hope it sticks! If not, let us know and we'll try to figure out why. In that case, this article might be relevant: How to fix preferences that won't save.